<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css" rel="stylesheet">
        .box{
            width: 100%;
            height: 100px;
            display: flex;
            flex-direction: row;
            align-items: center;
            border: 1px solid #3c3c3c;
        }
        .left{
            flex-basis: 100px;
            -webkit-flex-basis: 100px;
            background-color: red;
            height: 100%;
        }
        .right{
            background-color: blue;
            flex-grow: 1;
        }
        *{margin:0;padding:0;}
        #l{
            float: left;
            width: 220px;
            background-color: gray;
            height: 100px;
        }
        #r{
            background-color: orange;
            margin-left: 220px;
            height: 100px;
        }
    </style>
</head>
<body>
<div class="box">
    <div class="left">
    </div>
    <div class="right">
    </div>
</div>

<div id="l"></div>
<div id="r"></div>

</body>
</html>